Conventionally, in connection with electronic devices each including a plurality of elements, there have been proposed electronic devices of various types that can detect an abnormality in the elements. Specifically, for example, Patent Document 1 discloses an illumination apparatus that includes a circuit for detecting an abnormality in LEDs.
A description will be given of the illumination apparatus of Patent Document 1 with reference to the drawings. FIG. 10 is a block diagram showing a conventional illumination apparatus.
As shown in FIG. 10, an illumination apparatus 100 includes: X pieces of LED strings 1011 to 101X (where X is a natural number equal to or greater than 2), each string being formed by series-connected LEDs 200; a power supply unit 102 supplying power to the LEDs 200; a reference voltage generating unit 103 that divides supply voltage from the power supply unit 102 to generate reference voltage; X pieces of resistors 1041 to 104X that are connected in series to the LED strings 1011 to 101X to generate detection voltage that corresponds to current flowing through the LED strings 1011 to 101X; and X pieces of comparators 1051 to 105X that compare the detection voltage against the reference voltage for the respective LED strings 1011 to 101X to output an output signal COUT.
In the illumination apparatus 100, upon an occurrence of an abnormality in the LEDs or lines of any of the LED strings 1011 to 101X, one of the comparators 1051 to 105X that corresponds to the abnormal one of the LED strings 1011 to 101X outputs an output signal COUT indicative of the abnormality in the abnormal one of the LED strings 1011 to 101X.